Trump was seen as a presidential candidate who would possibly move towards a less interventionist foreign policy. That hope is gone. The insurgency that brought Trump to the top was defeated by a counter-insurgency campaign waged by the US military. (Historically its first successful one). The military has taken control of the White House process and it is now taking control of its policies.

It is schooling Trump on globalism and its "indispensable" role in it. Trump was insufficiently supportive of their desires and thus had to undergo reeducation:

When briefed on the diplomatic, military and intelligence posts, the new president would often cast doubt on the need for all the resources. Defense Secretary Jim Mattis and Secretary of State Rex Tillerson organized the July 20 session to lay out the case for maintaining far-flung outposts — and to present it, using charts and maps, in a way the businessman-turned-politician would appreciate.

Trump was hauled into a Pentagon basement "tank" and indoctrinated by the glittering four-star generals he admired since he was a kid:

The session was, in effect, American Power 101 and the student was the man working the levers. It was part of the ongoing education of a president who arrived at the White House with no experience in the military or government and brought with him advisers deeply skeptical of what they labeled the “globalist” worldview.In coordinated efforts and quiet conversations, some of Trump’s aides have worked for months to counter that view, hoping the president can be persuaded to maintain — if not expand — the American footprint and influence abroad.

Trump was sold the establishment policies he originally despised. No alternative view was presented to him.

It is indisputable that the generals are now ruling in Washington DC. They came to power over decades by shaping culture through their sponsorship of Hollywood, by manipulating the media through "embedded" reporting and by forming and maintaining the countries infrastructure through the Army Corps of Engineers. The military, through the NSA as well as through its purchasing power, controls the information flow on the internet. Until recently the military establishment only ruled from behind the scene. The other parts of the power triangle, the corporation executives and the political establishment, were more visible and significant. But during the 2016 election the military bet on Trump and is now, after he unexpectedly won, collecting its price.

Trump's success as the "Not-Hillary" candidate was based on an anti-establishment insurgency. Representatives of that insurgency, Flynn, Bannon and the MAGA voters, drove him through his first months in office. An intense media campaign was launched to counter them and the military took control of the White House. The anti-establishment insurgents were fired. Trump is now reduced to public figure head of a stratocracy - a military junta which nominally follows the rule of law.

Ultimate power to shape American foreign and security policy has fallen into the hands of three military men [...]...Being ruled by generals seems preferable to the alternative. It isn’t. ...[It] leads toward a distorted set of national priorities, with military “needs” always rated more important than domestic ones. ...It is no great surprise that Trump has been drawn into the foreign policy mainstream; the same happened to President Obama early in his presidency. More ominous is that Trump has turned much of his power over to generals. Worst of all, many Americans find this reassuring. They are so disgusted by the corruption and shortsightedness of our political class that they turn to soldiers as an alternative. It is a dangerous temptation.

The country has fallen to that temptation even on social-economic issues:

In the wake of the deadly racial violence in Charlottesville this month, five of the Joint Chiefs of Staff were hailed as moral authorities for condemning hate in less equivocal terms than the commander in chief did. ...On social policy, military leaders have been voices for moderation.

Kelly, Mattis and McMaster are not the only military figures serving at high levels in the Trump administration. CIA Director Mike Pompeo, Attorney General Jeff Sessions, Energy Secretary Rick Perry and Interior Secretary Ryan Zinke each served in various branches of the military, and Trump recently tapped former Army general Mark S. Inch to lead the Federal Bureau of Prisons....the National Security Council [..] counts two other generals on the senior staff.

This is no longer a Coup Waiting to Happen The coup has happened with few noticing it and ever fewer concerned about it. Everything of importance now passes through the Junta's hands:

[Chief of staff John] Kelly initiated a new policymaking process in which just he and one other aide [...] will review all documents that cross the Resolute desk. ...The new system [..] is designed to ensure that the president won’t see any external policy documents, internal policy memos, agency reports and even news articles that haven’t been vetted.

Staff who oppose [policy xyz] no longer have unfettered access to Trump, and nor do allies on the outside [.. .] Kelly now has real control over the most important input: the flow of human and paper advice into the Oval Office. For a man as obsessed about his self image as Trump, a new flow of inputs can make the world of difference.

The Trump insurgency against the establishment was marked by a mostly informal information and decision process. That has been destroyed and replaced:

Worried that Trump would end existing US spending/policies (largely, still geared to cold war priorities), the senior military staff running the Trump administration launched a counter-insurgency against the insurgency. ...General Kelly, Trump's Chief of Staff, has put Trump on a establishment-only media diet....In short, by controlling Trump's information flow with social media/networks, the generals smashed the insurgency's OODA loop (observe, orient, decide, act). Deprived of this connection, Trump is now weathervaning to cater to the needs of the establishment ...

The Junta members dictate their policies to Trump by only proposing to him certain alternatives. The one that is most preferable to them will be presented as the only desirable one. "There are no alternatives," Trump will be told again and again.

Thus we get a continuation of a failed Afghanistan policy and will soon get a militarily aggressive policy towards Iran.

Other countries noticed how the game has changed. The real decisions are made by the generals, Trump is ignored as a mere figurehead:

Asked whether he was predicting war [with North Korea], [former defence minister of Japan, Satoshi] Morimoto said: "I think Washington has not decided ... The final decision-maker is [US Defence Secretary] Mr Mattis ... Not the president."

Climate change, its local catastrophes and the infrastructure problems it creates within the US will further extend the military role in shaping domestic U.S. policy.

Nationalistic indoctrination, already at abnormal heights in the US society, will further increase. Military control will creep into ever extending fields of once staunchly civilian areas of policy. (Witness the increasing militarization of the police.)

It is only way to sustain the empire.

It is doubtful that Trump will be able to resist the policies imposed on him. Any flicker of resistance will be smashed. The outside insurgency which enabled his election is left without a figurehead, It will likely disperse. The system won.